He will say: "What we achieved was more than all but those with the most rosetinted spectacles thought was possible.

"But just because these issues are at the top of the agenda now, it doesn't mean they couldn't easily slip down again.

"We must not let that happen."

Mr Blair will announce a new, Africa Progress Panel, funded by Mr Gates and co-chaired by Mr Annan, to monitor the G8 aims. He will warn it will take "hard work for years to come" to tackle poverty in Africa but add: "We need to deliver the comprehensive package agreed at Gleneagles."

There is confusion on the amount of money handed over since the summit.

The G8 claims an extra #11.5billion has gone to the poorest countries. But Oxfam calculates only #2.75billion is "real money" with the rest debt cancellation.

G8 promised to raise aid to #71.5billion by 2010, including doubling aid to Africa.

About 20 of the poorest countries have had all their debts cancelled.

But campaigners are angry that plans for fair trade deals are not getting off the ground. Data, set up by Geldof, accused the "G8 money men" of "poverty of ambition".